1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Driver for voltage controller regulators 4 * 5 * Copyright (C) 2017 Google, Inc. 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/err.h> 10 #include <linux/init.h> 11 #include <linux/module.h> 12 #include <linux/of.h> 13 #include <linux/of_device.h> 14 #include <linux/regulator/coupler.h> 15 #include <linux/regulator/driver.h> 16 #include <linux/regulator/of_regulator.h> 17 #include <linux/sort.h> 18 19 #include "internal.h" 20 21 struct vctrl_voltage_range { 22 int min_uV; 23 int max_uV; 24 }; 25 26 struct vctrl_voltage_ranges { 27 struct vctrl_voltage_range ctrl; 28 struct vctrl_voltage_range out; 29 }; 30 31 struct vctrl_voltage_table { 32 int ctrl; 33 int out; 34 int ovp_min_sel; 35 }; 36 37 struct vctrl_data { 38 struct regulator_dev *rdev; 39 struct regulator_desc desc; 40 bool enabled; 41 unsigned int min_slew_down_rate; 42 unsigned int ovp_threshold; 43 struct vctrl_voltage_ranges vrange; 44 struct vctrl_voltage_table *vtable; 45 unsigned int sel; 46 }; 47 48 static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV) 49 { 50 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; 51 struct vctrl_voltage_range *out = &vctrl->vrange.out; 52 53 return ctrl->min_uV + 54 DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) * 55 (ctrl->max_uV - ctrl->min_uV), 56 out->max_uV - out->min_uV); 57 } 58 59 static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV) 60 { 61 struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl; 62 struct vctrl_voltage_range *out = &vctrl->vrange.out; 63 64 if (ctrl_uV < 0) { 65 pr_err("vctrl: failed to get control voltage\n"); 66 return ctrl_uV; 67 } 68 69 if (ctrl_uV < ctrl->min_uV) 70 return out->min_uV; 71 72 if (ctrl_uV > ctrl->max_uV) 73 return out->max_uV; 74 75 return out->min_uV + 76 DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) * 77 (out->max_uV - out->min_uV), 78 ctrl->max_uV - ctrl->min_uV); 79 } 80 81 static int vctrl_get_voltage(struct regulator_dev *rdev) 82 { 83 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 84 int ctrl_uV; 85 86 if (!rdev->supply) 87 return -EPROBE_DEFER; 88 89 ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev); 90 91 return vctrl_calc_output_voltage(vctrl, ctrl_uV); 92 } 93 94 static int vctrl_set_voltage(struct regulator_dev *rdev, 95 int req_min_uV, int req_max_uV, 96 unsigned int *selector) 97 { 98 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 99 int orig_ctrl_uV; 100 int uV; 101 int ret; 102 103 if (!rdev->supply) 104 return -EPROBE_DEFER; 105 106 orig_ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev); 107 uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV); 108 109 if (req_min_uV >= uV || !vctrl->ovp_threshold) 110 /* voltage rising or no OVP */ 111 return regulator_set_voltage_rdev(rdev->supply->rdev, 112 vctrl_calc_ctrl_voltage(vctrl, req_min_uV), 113 vctrl_calc_ctrl_voltage(vctrl, req_max_uV), 114 PM_SUSPEND_ON); 115 116 while (uV > req_min_uV) { 117 int max_drop_uV = (uV * vctrl->ovp_threshold) / 100; 118 int next_uV; 119 int next_ctrl_uV; 120 int delay; 121 122 /* Make sure no infinite loop even in crazy cases */ 123 if (max_drop_uV == 0) 124 max_drop_uV = 1; 125 126 next_uV = max_t(int, req_min_uV, uV - max_drop_uV); 127 next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV); 128 129 ret = regulator_set_voltage_rdev(rdev->supply->rdev, 130 next_ctrl_uV, 131 next_ctrl_uV, 132 PM_SUSPEND_ON); 133 if (ret) 134 goto err; 135 136 delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate); 137 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); 138 139 uV = next_uV; 140 } 141 142 return 0; 143 144 err: 145 /* Try to go back to original voltage */ 146 regulator_set_voltage_rdev(rdev->supply->rdev, orig_ctrl_uV, orig_ctrl_uV, 147 PM_SUSPEND_ON); 148 149 return ret; 150 } 151 152 static int vctrl_get_voltage_sel(struct regulator_dev *rdev) 153 { 154 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 155 156 return vctrl->sel; 157 } 158 159 static int vctrl_set_voltage_sel(struct regulator_dev *rdev, 160 unsigned int selector) 161 { 162 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 163 unsigned int orig_sel = vctrl->sel; 164 int ret; 165 166 if (!rdev->supply) 167 return -EPROBE_DEFER; 168 169 if (selector >= rdev->desc->n_voltages) 170 return -EINVAL; 171 172 if (selector >= vctrl->sel || !vctrl->ovp_threshold) { 173 /* voltage rising or no OVP */ 174 ret = regulator_set_voltage_rdev(rdev->supply->rdev, 175 vctrl->vtable[selector].ctrl, 176 vctrl->vtable[selector].ctrl, 177 PM_SUSPEND_ON); 178 if (!ret) 179 vctrl->sel = selector; 180 181 return ret; 182 } 183 184 while (vctrl->sel != selector) { 185 unsigned int next_sel; 186 int delay; 187 188 next_sel = max_t(unsigned int, selector, vctrl->vtable[vctrl->sel].ovp_min_sel); 189 190 ret = regulator_set_voltage_rdev(rdev->supply->rdev, 191 vctrl->vtable[next_sel].ctrl, 192 vctrl->vtable[next_sel].ctrl, 193 PM_SUSPEND_ON); 194 if (ret) { 195 dev_err(&rdev->dev, 196 "failed to set control voltage to %duV\n", 197 vctrl->vtable[next_sel].ctrl); 198 goto err; 199 } 200 vctrl->sel = next_sel; 201 202 delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out - 203 vctrl->vtable[next_sel].out, 204 vctrl->min_slew_down_rate); 205 usleep_range(delay, delay + DIV_ROUND_UP(delay, 10)); 206 } 207 208 return 0; 209 210 err: 211 if (vctrl->sel != orig_sel) { 212 /* Try to go back to original voltage */ 213 if (!regulator_set_voltage_rdev(rdev->supply->rdev, 214 vctrl->vtable[orig_sel].ctrl, 215 vctrl->vtable[orig_sel].ctrl, 216 PM_SUSPEND_ON)) 217 vctrl->sel = orig_sel; 218 else 219 dev_warn(&rdev->dev, 220 "failed to restore original voltage\n"); 221 } 222 223 return ret; 224 } 225 226 static int vctrl_list_voltage(struct regulator_dev *rdev, 227 unsigned int selector) 228 { 229 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 230 231 if (selector >= rdev->desc->n_voltages) 232 return -EINVAL; 233 234 return vctrl->vtable[selector].out; 235 } 236 237 static int vctrl_parse_dt(struct platform_device *pdev, 238 struct vctrl_data *vctrl) 239 { 240 int ret; 241 struct device_node *np = pdev->dev.of_node; 242 u32 pval; 243 u32 vrange_ctrl[2]; 244 245 ret = of_property_read_u32(np, "ovp-threshold-percent", &pval); 246 if (!ret) { 247 vctrl->ovp_threshold = pval; 248 if (vctrl->ovp_threshold > 100) { 249 dev_err(&pdev->dev, 250 "ovp-threshold-percent (%u) > 100\n", 251 vctrl->ovp_threshold); 252 return -EINVAL; 253 } 254 } 255 256 ret = of_property_read_u32(np, "min-slew-down-rate", &pval); 257 if (!ret) { 258 vctrl->min_slew_down_rate = pval; 259 260 /* We use the value as int and as divider; sanity check */ 261 if (vctrl->min_slew_down_rate == 0) { 262 dev_err(&pdev->dev, 263 "min-slew-down-rate must not be 0\n"); 264 return -EINVAL; 265 } else if (vctrl->min_slew_down_rate > INT_MAX) { 266 dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n", 267 vctrl->min_slew_down_rate); 268 return -EINVAL; 269 } 270 } 271 272 if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) { 273 dev_err(&pdev->dev, 274 "ovp-threshold-percent requires min-slew-down-rate\n"); 275 return -EINVAL; 276 } 277 278 ret = of_property_read_u32(np, "regulator-min-microvolt", &pval); 279 if (ret) { 280 dev_err(&pdev->dev, 281 "failed to read regulator-min-microvolt: %d\n", ret); 282 return ret; 283 } 284 vctrl->vrange.out.min_uV = pval; 285 286 ret = of_property_read_u32(np, "regulator-max-microvolt", &pval); 287 if (ret) { 288 dev_err(&pdev->dev, 289 "failed to read regulator-max-microvolt: %d\n", ret); 290 return ret; 291 } 292 vctrl->vrange.out.max_uV = pval; 293 294 ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl, 295 2); 296 if (ret) { 297 dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n", 298 ret); 299 return ret; 300 } 301 302 if (vrange_ctrl[0] >= vrange_ctrl[1]) { 303 dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n", 304 vrange_ctrl[0], vrange_ctrl[1]); 305 return -EINVAL; 306 } 307 308 vctrl->vrange.ctrl.min_uV = vrange_ctrl[0]; 309 vctrl->vrange.ctrl.max_uV = vrange_ctrl[1]; 310 311 return 0; 312 } 313 314 static int vctrl_cmp_ctrl_uV(const void *a, const void *b) 315 { 316 const struct vctrl_voltage_table *at = a; 317 const struct vctrl_voltage_table *bt = b; 318 319 return at->ctrl - bt->ctrl; 320 } 321 322 static int vctrl_init_vtable(struct platform_device *pdev, 323 struct regulator *ctrl_reg) 324 { 325 struct vctrl_data *vctrl = platform_get_drvdata(pdev); 326 struct regulator_desc *rdesc = &vctrl->desc; 327 struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl; 328 int n_voltages; 329 int ctrl_uV; 330 int i, idx_vt; 331 332 n_voltages = regulator_count_voltages(ctrl_reg); 333 334 rdesc->n_voltages = n_voltages; 335 336 /* determine number of steps within the range of the vctrl regulator */ 337 for (i = 0; i < n_voltages; i++) { 338 ctrl_uV = regulator_list_voltage(ctrl_reg, i); 339 340 if (ctrl_uV < vrange_ctrl->min_uV || 341 ctrl_uV > vrange_ctrl->max_uV) 342 rdesc->n_voltages--; 343 } 344 345 if (rdesc->n_voltages == 0) { 346 dev_err(&pdev->dev, "invalid configuration\n"); 347 return -EINVAL; 348 } 349 350 vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages, 351 sizeof(struct vctrl_voltage_table), 352 GFP_KERNEL); 353 if (!vctrl->vtable) 354 return -ENOMEM; 355 356 /* create mapping control <=> output voltage */ 357 for (i = 0, idx_vt = 0; i < n_voltages; i++) { 358 ctrl_uV = regulator_list_voltage(ctrl_reg, i); 359 360 if (ctrl_uV < vrange_ctrl->min_uV || 361 ctrl_uV > vrange_ctrl->max_uV) 362 continue; 363 364 vctrl->vtable[idx_vt].ctrl = ctrl_uV; 365 vctrl->vtable[idx_vt].out = 366 vctrl_calc_output_voltage(vctrl, ctrl_uV); 367 idx_vt++; 368 } 369 370 /* we rely on the table to be ordered by ascending voltage */ 371 sort(vctrl->vtable, rdesc->n_voltages, 372 sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV, 373 NULL); 374 375 /* pre-calculate OVP-safe downward transitions */ 376 for (i = rdesc->n_voltages - 1; i > 0; i--) { 377 int j; 378 int ovp_min_uV = (vctrl->vtable[i].out * 379 (100 - vctrl->ovp_threshold)) / 100; 380 381 for (j = 0; j < i; j++) { 382 if (vctrl->vtable[j].out >= ovp_min_uV) { 383 vctrl->vtable[i].ovp_min_sel = j; 384 break; 385 } 386 } 387 388 if (j == i) { 389 dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n", 390 vctrl->vtable[i].out); 391 /* use next lowest voltage */ 392 vctrl->vtable[i].ovp_min_sel = i - 1; 393 } 394 } 395 396 return 0; 397 } 398 399 static int vctrl_enable(struct regulator_dev *rdev) 400 { 401 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 402 403 vctrl->enabled = true; 404 405 return 0; 406 } 407 408 static int vctrl_disable(struct regulator_dev *rdev) 409 { 410 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 411 412 vctrl->enabled = false; 413 414 return 0; 415 } 416 417 static int vctrl_is_enabled(struct regulator_dev *rdev) 418 { 419 struct vctrl_data *vctrl = rdev_get_drvdata(rdev); 420 421 return vctrl->enabled; 422 } 423 424 static const struct regulator_ops vctrl_ops_cont = { 425 .enable = vctrl_enable, 426 .disable = vctrl_disable, 427 .is_enabled = vctrl_is_enabled, 428 .get_voltage = vctrl_get_voltage, 429 .set_voltage = vctrl_set_voltage, 430 }; 431 432 static const struct regulator_ops vctrl_ops_non_cont = { 433 .enable = vctrl_enable, 434 .disable = vctrl_disable, 435 .is_enabled = vctrl_is_enabled, 436 .set_voltage_sel = vctrl_set_voltage_sel, 437 .get_voltage_sel = vctrl_get_voltage_sel, 438 .list_voltage = vctrl_list_voltage, 439 .map_voltage = regulator_map_voltage_iterate, 440 }; 441 442 static int vctrl_probe(struct platform_device *pdev) 443 { 444 struct device_node *np = pdev->dev.of_node; 445 struct vctrl_data *vctrl; 446 const struct regulator_init_data *init_data; 447 struct regulator_desc *rdesc; 448 struct regulator_config cfg = { }; 449 struct vctrl_voltage_range *vrange_ctrl; 450 struct regulator *ctrl_reg; 451 int ctrl_uV; 452 int ret; 453 454 vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data), 455 GFP_KERNEL); 456 if (!vctrl) 457 return -ENOMEM; 458 459 platform_set_drvdata(pdev, vctrl); 460 461 ret = vctrl_parse_dt(pdev, vctrl); 462 if (ret) 463 return ret; 464 465 ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl"); 466 if (IS_ERR(ctrl_reg)) 467 return PTR_ERR(ctrl_reg); 468 469 vrange_ctrl = &vctrl->vrange.ctrl; 470 471 rdesc = &vctrl->desc; 472 rdesc->name = "vctrl"; 473 rdesc->type = REGULATOR_VOLTAGE; 474 rdesc->owner = THIS_MODULE; 475 rdesc->supply_name = "ctrl"; 476 477 if ((regulator_get_linear_step(ctrl_reg) == 1) || 478 (regulator_count_voltages(ctrl_reg) == -EINVAL)) { 479 rdesc->continuous_voltage_range = true; 480 rdesc->ops = &vctrl_ops_cont; 481 } else { 482 rdesc->ops = &vctrl_ops_non_cont; 483 } 484 485 init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc); 486 if (!init_data) 487 return -ENOMEM; 488 489 cfg.of_node = np; 490 cfg.dev = &pdev->dev; 491 cfg.driver_data = vctrl; 492 cfg.init_data = init_data; 493 494 if (!rdesc->continuous_voltage_range) { 495 ret = vctrl_init_vtable(pdev, ctrl_reg); 496 if (ret) 497 return ret; 498 499 /* Use locked consumer API when not in regulator framework */ 500 ctrl_uV = regulator_get_voltage(ctrl_reg); 501 if (ctrl_uV < 0) { 502 dev_err(&pdev->dev, "failed to get control voltage\n"); 503 return ctrl_uV; 504 } 505 506 /* determine current voltage selector from control voltage */ 507 if (ctrl_uV < vrange_ctrl->min_uV) { 508 vctrl->sel = 0; 509 } else if (ctrl_uV > vrange_ctrl->max_uV) { 510 vctrl->sel = rdesc->n_voltages - 1; 511 } else { 512 int i; 513 514 for (i = 0; i < rdesc->n_voltages; i++) { 515 if (ctrl_uV == vctrl->vtable[i].ctrl) { 516 vctrl->sel = i; 517 break; 518 } 519 } 520 } 521 } 522 523 /* Drop ctrl-supply here in favor of regulator core managed supply */ 524 devm_regulator_put(ctrl_reg); 525 526 vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg); 527 if (IS_ERR(vctrl->rdev)) { 528 ret = PTR_ERR(vctrl->rdev); 529 dev_err(&pdev->dev, "failed to register regulator: %d\n", ret); 530 return ret; 531 } 532 533 return 0; 534 } 535 536 static const struct of_device_id vctrl_of_match[] = { 537 { .compatible = "vctrl-regulator", }, 538 {}, 539 }; 540 MODULE_DEVICE_TABLE(of, vctrl_of_match); 541 542 static struct platform_driver vctrl_driver = { 543 .probe = vctrl_probe, 544 .driver = { 545 .name = "vctrl-regulator", 546 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 547 .of_match_table = of_match_ptr(vctrl_of_match), 548 }, 549 }; 550 551 module_platform_driver(vctrl_driver); 552 553 MODULE_DESCRIPTION("Voltage Controlled Regulator Driver"); 554 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>"); 555 MODULE_LICENSE("GPL v2"); 556